1. Field
One embodiment of the invention relates to improvements in a device and method for error correcting encoding processing on a digital information sequence.
2. Description of the Related Art
As is well known, in a system for recording a digital information sequence that corresponds to video, audio and the like on an information recording medium such as a disk and a tape and reproducing such a sequence from such a medium, an ECC (error correcting code) parity is added to a digital information sequence to be recorded. And then a modulation processing, such as to limit the number of sequential zeros within a predetermined number, to meet a request from recording/reproducing system is performed.
In contrast, as disclosed in a document (IEEE TRANSACTION ON INFORMATION THEORY, VOL. 44, NO. 4, JULY 1998), recently encoding means (which is referred to as reverse ECC in some cases) has been developed which adds an ECC parity to a digital information sequence to be recorded by performing first modulation processing to meet a request from a recording/reproducing system and then performs second modulation processing to meet a request from the recording/reproducing system on the added ECC parity.
However, the encoding means described in the document needs to perform modulation processing twice, that is, the first modulation processing performed on an original digital information sequence and the second modulation processing performed on an ECC parity of the sequence, so that the encoding means has a complicated configuration and a number of bits of data to be recorded gets big.